The present invention relates to a vascular plug delivery system and, more particularly, to a device and method for in vivo delivery of a vascular plug to the site of a puncture in a blood vessel.
Various medical procedures require a physician to insert and advance a catheter or similar device into a patient's blood vessel. Typically, the blood vessel is first punctured with a needle. Thereafter, a guidewire is advanced through the puncture into the vessel. A dilator may or may not be employed to expand the size of the puncture in the vessel. Next, the catheter is advanced over the guidewire and into the blood vessel. The physician then performs the necessary medical procedure and withdraws the catheter, guidewire, etc. from the patient.
Following the withdrawal of the catheter (or similar device) from the patient's blood vessel, it is necessary to control the bleeding until the puncture has clotted. The most common method for controlling this bleeding involves having a nurse or other trained professional apply direct compression to the site of the puncture. Such a technique, however, is not without risk. Applying too much pressure can result in a decrease of blood circulation to distal limbs, while too little pressure leads to bleeding that may create hematomas or aneurysms. Moreover, the compression technique is very time consuming (averaging 1/2 hour to 1 hour) and, hence, expensive.
The prior art has suggested several alternative techniques for controlling the flow of blood following a catheterization procedure. For example, U.S. Pat. Nos. 4,744,364 and 4,852,568 disclose a method whereby a tubular body is inserted through the puncture following catheterization and an expandable plug is dispensed from the tubular body into the vessel and pulled taught against the interior wall of the vessel. The method, however, carries with it the inherent risks associated with introducing foreign objects into the blood vessel and, in addition, may prove difficult when deploying a closure in a relatively small-sized vessel. Further, it is difficult to ensure that the physician will be able to relocate the puncture in the vessel when introducing the tubular body (the guidewire having already been withdrawn).
Next, the Datascope Corporation of Montvale, N.J. has introduced a device called Vasoseal for sealing vascular punctures. The physician, at the beginning of the procedure, calculates the distance between the skin surface and the arterial surface. After the catheterization procedure, the physician chooses a plug system having a length corresponding to the original calculation and, thereafter, inserts a bottom and top plug into the tissue channel. However, because of various factors that may occur during the catheterization procedure (e.g., swelling of the local area) the initial length calculation performed by the physician may no longer be accurate. In addition, because only the tissue channel is guiding the plugs to the puncture, it is difficult to ensure that the plugs are, in fact, positioned at the puncture.
An additional technique is disclosed in U.S. Pat. No. 5,108,421, which relates to an assembly for position-ing a plug into a tissue channel. The assembly includes a catheter sheath, which is first inserted through the puncture in the blood vessel. A balloon catheter is then inserted through the sheath and, thereafter, the sheath is removed. Next, the balloon is inflated inside the vessel such that the balloon presses against the interior wall of the vessel at the puncture site. A plug is thereafter inserted into the tissue channel until the distal end of such plug contacts the balloon. The balloon is then deflated and the catheter removed. The technique, although minimizing the likelihood of delivering the plug into the vessel, includes the step of inflating a balloon in the vessel, a procedure which involves decreasing the circulation of blood through the vessel. In addition, because the balloon catheter is still deployed in the vessel at the time the plug is inserted, it is difficult to ensure that the entire puncture site will be covered by the plug after the catheter is withdrawn.
Finally, European Patent Application No. 476,178 A1 discloses a device for placing a plug at the site of a puncture in a blood vessel. The device includes a tube arrangement that may be advanced over a previously-positioned guidewire. After the tube contacts the wall of the vessel, the guidewire is withdrawn. A plug is then advanced through the tube arrangement to the puncture site. Because the guidewire has been withdrawn, it is difficult to ensure that the tube is still properly located at the puncture site at the time of delivery (e.g., the tube may have shifted during withdrawal of the guidewire or during insertion of the plug). In addition, the device provides no independent means for informing the physician that the tube arrangement has been completely advanced to the puncture site. Stated differently, in placing the plug, the physician is forced to rely only on the tactile sensation provided by the tube arrangement contacting the outer wall of the vessel, thereby introducing the possibility that the physician will advance the tube arrangement into the puncture and actually deliver the plug in the vessel itself or, alternatively, will not advance the tube arrangement far enough, which will deliver the plug a distance away from the puncture and allow bleeding from the vessel.
In light of the prior art, it would be desirable to provide a device for accurately and consistently delivering a vascular plug to the site of a puncture in a blood vessel, thereby ensuring complete hemostasis of the arterial puncture. This delivery should be accomplished with minimum additional intrusion to the blood vessel itself.